What aspect of beer is largely influenced by the fermentation process?

The fermentation process plays a crucial role in determining the alcohol content of beer. During fermentation, yeast converts the fermentable sugars present in the wort into alcohol and carbon dioxide. The type and amount of sugars, as well as the specific yeast strain used, significantly influence the final alcohol by volume (ABV) of the finished beer. Different yeast strains can also have varying efficiencies in converting sugars into alcohol, leading to different alcohol content levels.

Bitterness, while it can be influenced by fermentation to some extent, is primarily determined by the types and quantities of hops added during the brewing process, particularly during the boiling stage. Aromas in beer can be affected by both the ingredients used and fermentation, but they are largely a result of hop choices and the specific fermentation characteristics imparted by the yeast. Appearance is determined by the malt used, the brewing method, and how the beer is processed, making it less reliant on fermentation alone.